three-decker

[three-dek-er] /ˈθriˈdɛk ər/
noun
1.
any ship having three decks, tiers, etc.
2.
(formerly) one of a class of sailing warships that carried guns on three decks.
3.
a sandwich made of three slices of bread interlaid with two layers of filling; club sandwich.
4.
something having three layers, levels, or tiers.
Also called triple-decker (for defs 3, 4).
Origin
1785-95
British Dictionary definitions for three-decker

three-decker

noun
1.
  1. anything having three levels or layers
  2. (as modifier): a three-decker sandwich
2.
a warship with guns on three decks